Format you SD card to FAT32, download the file in my post, unzip it in your PC, then copy and past the content to your SD card.You will not disable your nav unit,
Now go to this thread and follow post #55 and 56, even tho your unit is not 930bt, steps are the same.
After you're done, eject sd card and then reboot HU.
Hackmode+Supertestmode.rar